Modem Functional Test with the Data Channel

Last updated: December 3, 2008

This section is only applicable to the lab applications.

The Data Channel enables testing of wireless modems or GPRS devices with built-in modems, typically using dial-up connections. If the modem is not built-in, it is usually controlled from another device such as a PC.

Before you use the Data channel for modem testing, you must have the following information:

an IP address valid for the subnet that you will connect the test set to
the valid subnet mask for that subnet
the default gateway for that network
a valid IP address for the modem or its controlling PC (even though the modem is the Device Under Test (DUT), typically a PC will be assigned the IP address)

NOTE

There are restrictions regarding IP Addresses that are valid for use. See IP Address Requirements for more information.

A. Hardware Connections

Connect Logging PC to LAN

Please consult with your IT department if you need assistance connecting your PC to the LAN. Refer to Protocol Logging for more information about setting up protocol logging.

Connect Test Set to LAN

Connect the LAN port on the back of the test set to your LAN.

Connect DUT (Modem and Control PC) to the Test Set

Connect the modem to the PC as appropriate for your application.
Connect the DUT to the test set.

B. Test Set and DUT Setup

Set Up Test Set

Press the Sys Config key to display the System Config screen.
Use the Instrument Setup softkey ( F1 ) to display the Instrument Setup menu.
Enter the IP address for the test set.
Use the same menu to set the Subnet Mask.
Use the same menu to set the Default Gateway.
Press the Call Setup key to go to the Call Setup screen on the test set.
Select Data Conn Type and set the field to IP Data .
Press the left More key to go to the second screen of the Control menu.
Select DUT PDP Setup to open the DUT PDP Setup menu on the test set.
Set the DUT's IP address (or the address of the controlling PC) in the DUT PDP Setup menu on the test set.
Note: The entered IP address must be on the same subnet as the test set.

Set Up DUT

You may need to set the IP address or other network parameters in the controlling PC or the GPRS device. Set these as needed.
If using a dial-up connection, you may need to set up Dial-Up Networking in your PC. Do this as needed.

C. Modem Functional Test

In order to test the functioning of the DUT, it must first complete a successful PDP Context activation. With the test set this involves two steps:

First, the DUT must perform a GPRS attach.

Connect the DUT to the RF IN/OUT port of the test set.
Turn the DUT on and wait for Attached to appear in the Active Cell: field on the test set's front panel display. Some modems may need to attempt data transfer before it attaches to the test set. Sometimes the modem will attach if the number *99# is dialed.

For DUTs that don't perform a GPRS attach automatically, you may have to set the DUT to data mode.

Second, the DUT must request a PDP Context Activation.

Use the DUT to initiate data transfers. The DUT will request an activation, an IP address will be assigned by the test set, and the PDP Context will be active.
This can be observed by looking for "PDP Active" in the Active Cell Status: field.

You can also perform some measurements while using the Data Channel:

BLER measurements are supported.
TX measurements are supported.
BER measurements are not supported.
Logging is possible during Data Channel operation.

How do You Know When You Have Succeeded?

You have made a successful data connection if you can:

Browse the Internet over the DUT.
See data transfer in both directions by observing the Counters field in the Call Setup screen of the test set.
Look at the DUT and its PC and verify that the data you were trying to transfer has actually transferred.